Inducing Fe 3d Electron Delocalization and Spin-State Transition of FeN4 Species Boosts Oxygen Reduction Reaction for Wearable Zinc–Air Battery

Abstract

HighlightsThe strong interaction between Ti3C2Sx and FeN4 species induces the central metal Fe(II) in FeN4 species with intermediate spin state transferred to high spin state, in which the latter is favorable to initiate the reduction of oxygen.This strong interaction induces a remarkable Fe 3d electron delocalization with d band center upshift, boosting oxygen-containing groups adsorption on FeN4 species and oxygen reduction reaction kinetics.The resulting FeN4–Ti3C2Sx with FeN4 moieties in high spin state exhibits high half-wave potential of 0.89 V vs. RHE and high limiting current density of 6.5 mA cm−2, enabling wearable zinc–air battery showing a good discharge performance with a maximum power density of 133.6 mW cm−2.